Supercomputers, Not Wind Tunnels

During the 2010 Winter Olympics, the three U.S. bobsled teams will be competing in the bobsleigh event with their fastest-ever four-man bobsled. In the past, designers spent hundreds of hours building bobsled mock-ups in wind tunnels, making subtle changes, and then retesting--a labor-intensive process that didn't allow precise measurements of how subtle changes could bring improvements. Today, that's no longer the case. One of the U.S. crews, Team Night Train, uses powerful IBM supercomputers along with specialized fluid dynamics software from Exa Corporation to run computerized simulations that shave valuable tenths and hundredths of a second off Night Train's times. The goal: earning Team USA's first Olympic gold medal since 1948. (Photo: TeamUSA.org)

Ice and Aerodynamics

This image shows some of the magic at work. Supercomputers and Exa PowerFlow software combine to improve the aerodynamic performance (shown by the green streamlines) of the sled by simulating the airflow over the vehicle as designers make each change. How effective has this approach been? Unbelievably so: The four-man Night Train team used the technology to design, hone, and build its amazingly fast bobsled, which won the 2009 World Championship last February in Lake Placid, New York--the first such title for a U.S. team in 50 years. Team Night Train hopes to transform that success into a gold medal in these Olympics when the bobsled events begin February 20. (Image: Exa Corporation)

Slipping Through Air

In this image, the PowerFlow software shows sled designers a computer-generated visualization of complex, turbulent airflow that travels over the centerline of the sled and the four-man crew on a run. The designers with the Bo-Dyn Bobsled Project, which built Night Train's sled, can then change the design based on the simulations and make adjustments on the fly--much faster than before--to help cut turbulence and make the sled slip through the air more quickly. Last month Team Night Train used its sled to win the 2010 World Cup championship--the first time a U.S. team has won that title in 17 years. (Image: Exa Corporation)

'Low-Speed Wake'

Improving the airflow over the front of the bobsled isn't the only key to reducing aerodynamic drag. This simulated image shows, in the light blue trailing colors, the "low-speed wake" that's created in the rear of the sled as it slices through the air on its runs down the curvy tracks of the competitive bobsled circuit. Reducing this wake is also critical to cutting the sled's times. Last month, Team Night Train won the first World Cup title for the United States in 17 years largely due to the huge aerodynamic gains made possible by high-performance computing and complex simulations. (Image: Exa Corporation)

19 Teraflops of IBM Computing Power

On the bobsled tracks, carving hundredths of a second from a team's runs can make the difference between a gold medal and also-ran status. For help in generating simulated images that allow sled engineers to achieve such gains, the designers turn to a supercomputer, which they use on an as-needed, on-demand basis via IBM's high-performance cloud network. The network consists of a cluster of 384 IBM System x3550 and x3450 blade servers, each with 8GB of RAM--all amounting to more than 19 teraflops of computing power at its peak. Each image like the one shown here takes about 8 hours for the software to generate. (Image: Exa Corporation)

Getting the Red Out

The enemy of a bobsled is wind resistance--primarily high pressure, which appears as red on the sled body and the crew helmets in this computer-generated simulated image. Sled designers can take an image like this and modify the sled to reduce the red areas--where the wind resistance is highest--using Exa's PowerViz software. The designers can then compare and contrast changes of even just a few millimeters on the same image, to find improvements and shave times. This gives Team Night Train an advantage because their designers can tweak the sled very subtly and produce results that drop their times on the track. (Image: Exa Corporation)

Simulations and Streamribbons

By reducing drag through computerized modeling, simulations, and testing, the Bo-Dyn bobsled designers have been able to drastically improve the aerodynamic efficiency of the Night Train sled, and even its crew. In this simulation image, the green "streamribbons" at the rear of the sled show the movement of airflow around the sled and crew, resulting in undesirable drag that the engineers can work to minimize. Before such simulations on the on-demand supercomputer, these kinds of tests had to be performed manually with mock-ups in a wind tunnel. What could take days or weeks now takes only about 8 hours. (Image: Exa Corporation)

Two-Mans, Too

The four-man Night Train sled isn't the only one to get development help from the Exa software and IBM hardware. Once Night Train was on schedule with its improvements, the design team's attention turned to the two-man bobsled. In this image generated by the PowerFlow software, the important role of the driver's aerodynamic wake is highlighted, with the blue color indicating low pressure that pulls back on the driver and sled to add wind resistance. The rear crew member is completely tucked in and not contributing to resistance, which is the desired result. (Image: Exa Corporation)

Pressure Drop

Here's where it all comes together for the design team. In this simulated image an Exa PowerFlow graphic is overlaid onto a photograph of a U.S. bobsled on a track to show the real-world effects of wind resistance during a run. The red areas again show high surface pressure--which is what engineers want to decrease--while the blue regions represent low pressure. The goal is always to reduce frontal high pressure to quicken the sled's path through the air, while also trying not to increase low pressure at the rear, which can slow the sled. (Image: Exa Corporation)

The Moment of Truth

The four-man bobsled team, led by driver Steven Holcomb, celebrates last February after one of the runs that led to the team's gold-medal victory at the 2009 World Championship in Lake Placid, New York. The development of the Night Train sled using Exa software and IBM on-demand supercomputing power has been helping to put the sled and its crew in the winner's circle for the last several years. Will that streak continue in the Winter Games? Stay tuned to the Olympics for the answer. (Photo: Charlie Booker)

The Sleigh Men

The people behind the success of Team Night Train. Standing from left to right: John Morgan, executive director of the Bo-Dyn Bobsled Project; sled driver Steve Holcomb; sled crew member Curt Tomaseivcz; sled crew member Steve Mesler; Bo-Dyn sled builder Bob Cuneo; sled crew member Justin Olsen; and Brad Duncan, director of aerodynamics for Exa Corporation. Sitting on the sled is former NASCAR stock-car racer Geoff Bodine, who funded the Bo-Dyn Bobsled Project after he learned that the U.S. team had not been competitive for decades. (Photo: TeamUSA.org)

(Todd R. Weiss is a freelance technology journalist who formerly wrote for Computerworld.com. Follow him on Twitter at www.twitter.com/TechManTalking)